'Stuffed' nanotubes could enable high-density storage

DRESDEN, Germany  Researchers here have succeeded in loading carbon nanotubes with magnetic materials, an advance that could enable the use of the tiny cylinders for making extremely high-density data storage devices.

The Leibniz-Institut f¼r Festkrper und Werkstoffforschung Dresden (IFW) said it was able to stuff nanotubes for the first time with iron, cobalt or nickel. All of the materials have magnetic properties. The nanotubes have a diameter of about 10 nm. Researchers at the institute were able to grow the tubes on structured silicon wafers.

Scientists said they hope to use stuffed nanotubes to make nonvolatile memory. The small dimensions could theoretically allow a 1,000-fold increase in storage density compared to semiconductor based DRAM cells, said IFW's Albrecht Leonhard. Another application of these tubes would be as tiny magnets, he added.

The Dresdner institute used chemical vapor deposition to make the tubes, a process normally used for semiconductor production. Stuffing the nanotubes was accomplished while the tubes were grown using the deposition process. The location for tube growth on a wafer is determined by the deposition of tiny amounts of iron particles. According to the scientists, this allows the growth of defined structures on the wafer.

According to Albrecht, the institute has succeeded in growing "several milligram" nanotubes. The scientists are now looking for an investor such as a semiconductor manufacturer to standardize the process to the point where it could be used for production.